Question

1. to make it possible for the arm motor to lift the arm on the clawbot

a the motor runs at double the normal voltage
b the gears increase the torque and decrease the speed available at the arm.
c the gears increase the speed and decrease the torque available at the arm
d the gears decrease the torque and decrease the speed available at the arm
e the gears increase the speed and increase the torque available at the arm

Explanation:

Step1: Analyze option A

Running the motor at double voltage might damage the motor and is not a standard, safe way to ensure lifting.

Step2: Analyze option B

Gears can be used in a gear - reduction system. In a gear - reduction system, the relationship between torque (\(T\)) and speed (\(\omega\)) is given by the formula \(P = T\omega\) (where \(P\) is power, assuming power is approximately constant for a motor in a short - term operation, neglecting losses). If we want to increase the torque at the arm (to lift it, we need more torque), we can decrease the speed. A gear - reduction system (where the number of teeth on the driven gear \(N_2\) is greater than the number of teeth on the driving gear \(N_1\), \(N_2>N_1\)) will increase the torque (\(T_2=\frac{N_2}{N_1}T_1\)) and decrease the speed (\(\omega_2=\frac{N_1}{N_2}\omega_1\)).

Step3: Analyze option C

Increasing speed while decreasing torque is the opposite of what is needed for lifting (which requires more torque).

Step4: Analyze option D

Decreasing torque is not helpful for lifting.

Step5: Analyze option E

Increasing speed while increasing torque is not in line with the power - torque - speed relationship (\(P = T\omega\)) for a gear system (assuming power is approximately constant).

Answer:

B. The gears increase the torque and decrease the speed available at the arm.